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United States Patent | 6,169,634 |
Sirat | January 2, 2001 |
A method and apparatus for converting a beam of light that is substantially coherent and has a coherence length into substantially incoherent radiation. The method has the steps of collimating the beam, delaying a first portion of the beam by a first optical delay by ballistic passage through a first cell of an optical element, and delaying each of a plurality of other portions of the beam by an optical delay different from the first optical delay by an amount exceeding the coherence length of the beam.
Inventors: | Sirat; Gabriel Y. (Jerusalem, IL) |
Assignee: | Optimet, Optical Metrology Ltd (Jerusalem, IL) |
Appl. No.: | 312448 |
Filed: | May 14, 1999 |
Current U.S. Class: | 359/641; 359/317; 359/572; 359/722 |
Intern'l Class: | G02B 027/30 |
Field of Search: | 359/641,317,572 353/722 |
4521075 | Jun., 1985 | Obenschain et al. | 350/162. |
4619508 | Oct., 1986 | Shibuya | 353/122. |
4744615 | May., 1988 | Fan et al. | 350/96. |
Foreign Patent Documents | |||
1 136 457 | Nov., 1982 | CA. | |
WO 97/42891 | Nov., 1997 | WO. |
Ripin, Barrett H., Induced Spatial Incoherence Optical Delay Element, Navy Technical Disclosure Bulletin, vol. 10, No. 4, Jun. 1985 (1985-06), pp. 25-32 XP002112467. McKechnie, T.S., "Speckle Reduction", in Dainty, J.C., Laser Speckle and Related Phenomena, XP002112684, Chapter 4, pp. 123-170, Berlin (1975). |